Metabolic origins and clinical significance of LDL heterogeneity

The Application of a Modified d-ROMs Test for Measurement of Oxidative Stress and Oxidized High-Density Lipoprotein

Reactive oxygen species (ROS) are involved in the initiation and progression of atherosclerosis. ROS-derived hydroperoxides, as an indicator of ROS production, have been measured by using the diacron reactive oxygen metabolites (d-ROMs) test, which requires iron-containing transferrin in the reaction mixture. In this study we developed a modified d-ROMs test, termed the Fe-ROMs test, where iron ions were exogenously added to the reaction mixture. This modification is expected to exclude the assay variation that comes from different blood iron levels in individuals. In addition, this Fe-ROMs test was helpful for determining the class of plasma lipoproteins that are hydroperoxidized. Low-density lipoprotein/very low-density lipoprotein (LDL/VLDL) and high-density lipoprotein (HDL) were purified by use of an LDL/VLDL purification kit and the dextran sulfate-Mg²⁺ precipitation method, respectively; their hydroperoxide contents were assessed by performing the Fe-ROMs test. The majority of the hydroperoxides were detected only in the HDL fraction, not in the LDL/VLDL. Further detailed analysis of HDLs by size-exclusion high-performance liquid chromatography revealed that the hydroperoxide-containing molecules were small-sized HDLs. Because HDL was shown to be the principal vehicle for the plasma hydroperoxides, this Fe-ROMs test is a beneficial method for the assessment of oxidized-HDL levels. Indeed, Fe-ROMs levels were strongly associated with the levels of oxidized HDL, which were determined by performing the malondialdehyde-modified HDL enzyme immunoassay. In conclusion, the Fe-ROMs test using plasma itself or the HDL fraction after dextran sulfate-Mg²⁺ precipitation is useful to assess the functionality of HDL, because the oxidation of HDL impairs its antiatherogenic capacity.

Impact of a 6-week non-energy-restricted ketogenic diet on physical fitness, body composition and biochemical parameters in healthy adults

BACKGROUND

The ketogenic diet (KD) is a very low-carbohydrate, high-fat and adequate-protein diet that without limiting calories induces different metabolic adaptations, eg, increased levels of circulating ketone bodies and a shift to lipid metabolism. Our objective was to assess the impact of a 6-week non-energy-restricted KD in healthy adults beyond cohorts of athletes on physical performance, body composition, and blood parameters.

METHODS

Our single arm, before-and-after comparison study consisted of a 6-week KD with a previous preparation period including detailed instructions during classes and individual counselling by a dietitian. Compliance with the dietary regimen was monitored by measuring urinary ketones daily, and 7-day food records. All tests were performed after an overnight fast: cardiopulmonary exercise testing via cycle sprioergometry, blood samples, body composition, indirect calorimetry, handgrip strength, and questionnaires addressing complaints and physical sensations.

RESULTS

Forty-two subjects aged 37 ± 12 years with a BMI of 23.9 ± 3.1 kg/m² completed the study. Urinary ketosis was detectable on 97% of the days, revealing very good compliance with the KD. Mean energy intake during the study did not change from the habitual diet and 71.6, 20.9, and 7.7% of total energy intake were from fat, protein, and carbohydrates, respectively. Weight loss was -2.0 ± 1.9 kg (P < 0.001) with equal losses of fat-free and fat mass. VO₂peak and peak power decreased from 2.55 ± 0.68 l/min to 2.49 ± 0.69 l/min by 2.4% (P = 0.023) and from 241 ± 57 W to 231 ± 57 W by 4.1% (P < 0.001), respectively, whereas, handgrip strength rose slightly from 40.1 ± 8.8 to 41.0 ± 9.1 kg by 2.5% (P = 0.047). The blood lipids TG and HDL-C remained unchanged, whereas total cholesterol and LDL-C increased significantly by 4.7 and 10.7%, respectively. Glucose, insulin, and IGF-1 dropped significantly by 3.0, 22.2 and 20.2%, respectively.

CONCLUSIONS

We detected a mildly negative impact from this 6-week non-energy-restricted KD on physical performance (endurance capacity, peak power and faster exhaustion). Our findings lead us to assume that a KD does not impact physical fitness in a clinically relevant manner that would impair activities of daily living and aerobic training. However, a KD may be a matter of concern in competitive athletes.

TRIAL REGISTRATION

DRKS00009605, registered 08 January 2016.

[Atherogenic modification of low-density lipoproteins]

One of the first manifestations of atherosclerosis is accumulation of extra- and intracellular cholesterol esters in the arterial intima. Formation of foam cells is considered as a trigger in the pathogenesis of atherosclerosis. Low density lipoprotein (LDL) circulating in human blood is the source of lipids accumulated in the arterial walls. This review considered features and role in atherogenesis different modified forms of LDL: oxidized, small dense, electronegative and especially desialylated LDL. Desialylated LDL of human blood plasma is capable to induce lipid accumulation in cultured cells and it is atherogenic. LDL possesses numerous alterations of protein, carbohydrate and lipid moieties and therefore can be termed multiple-modified LDL. Multiple modification of LDL occurs in human blood plasma and represents a cascade of successive changes in the lipoprotein particle: desialylation, loss of lipids, reduction in the particle size, increase of surface electronegative charge, etc. In addition to intracellular lipid accumulation, stimulatory effects of naturally occurring multiple-modified LDL on other processes involved in the development of atherosclerotic lesions, namely cell proliferation and fibrosis, were shown.

Effects of a very high saturated fat diet on LDL particles in adults with atherogenic dyslipidemia: A randomized controlled trial

Background

Previous studies have shown that increases in LDL-cholesterol resulting from substitution of dietary saturated fat for carbohydrate or unsaturated fat are due primarily to increases in large cholesterol-enriched LDL, with minimal changes in small, dense LDL particles and apolipoprotein B. However, individuals can differ by their LDL particle distribution, and it is possible that this may influence LDL subclass response.

Objective

The objective of this study was to test whether the reported effects of saturated fat apply to individuals with atherogenic dyslipidemia as characterized by a preponderance of small LDL particles (LDL phenotype B).

Methods

Fifty-three phenotype B men and postmenopausal women consumed a baseline diet (55%E carbohydrate, 15%E protein, 30%E fat, 8%E saturated fat) for 3 weeks, after which they were randomized to either a moderate carbohydrate, very high saturated fat diet (HSF; 39%E carbohydrate, 25%E protein, 36%E fat, 18%E saturated fat) or low saturated fat diet (LSF; 37%E carbohydrate, 25%E protein, 37%E fat, 9%E saturated fat) for 3 weeks.

Results

Compared to the LSF diet, consumption of the HSF diet resulted in significantly greater increases from baseline (% change; 95% CI) in plasma concentrations of apolipoprotein B (HSF vs. LSF: 9.5; 3.6 to 15.7 vs. -6.8; -11.7 to -1.76; p = 0.0003) and medium (8.8; -1.3 to 20.0 vs. -7.3; -15.7 to 2.0; p = 0.03), small (6.1; -10.3 to 25.6 vs. -20.8; -32.8 to -6.7; p = 0.02), and total LDL (3.6; -3.2 to 11.0 vs. -7.9; -13.9 to -1.5; p = 0.03) particles, with no differences in change of large and very small LDL concentrations. As expected, total-cholesterol (11.0; 6.5 to 15.7 vs. -5.7; -9.4 to -1.8; p<0.0001) and LDL-cholesterol (16.7; 7.9 to 26.2 vs. -8.7; -15.4 to -1.4; p = 0.0001) also increased with increased saturated fat intake.

Conclusions

Because medium and small LDL particles are more highly associated with cardiovascular disease than are larger LDL, the present results suggest that very high saturated fat intake may increase cardiovascular disease risk in phenotype B individuals. This trial was registered at clinicaltrials.gov (NCT00895141).

Trial registration

Clinicaltrials.gov NCT00895141.

Oxidized LDL Is Associated With Metabolic Syndrome Traits Independently of Central Obesity and Insulin Resistance

This study assesses whether oxidative stress, using oxidized LDL (ox-LDL) as a proxy, is associated with metabolic syndrome (MS), whether ox-LDL mediates the association between central obesity and MS, and whether insulin resistance mediates the association between ox-LDL and MS. We examined baseline data from 3,987 subjects without diabetes in the Progression of Early Subclinical Atherosclerosis (PESA) Study. For the second, third, and fourth ox-LDL quartiles versus the first, the odds ratios (95% CI) for MS were 0.84 (0.52, 1.36), 1.47 (0.95, 2.32), and 2.57 (1.66, 4.04) (P < 0.001 for trend) once adjusted for age, sex, smoking, LDL-cholesterol, BMI, waist circumference, and HOMA-insulin resistance (HOMA-IR). Results showing the same trend were found for all MS components except glucose concentration. Ox-LDL mediated 13.9% of the association of waist circumference with triglycerides and only 1-3% of the association with HDL-cholesterol, blood pressure, and insulin concentration. HOMA-IR did not mediate the association between ox-LDL and MS components. This study found higher ox-LDL concentrations were associated with MS and its components independently of central obesity and insulin resistance. Ox-LDL may reflect core mechanisms through which MS components develop and progress in parallel with insulin resistance and could be a clinically relevant predictor of MS development.

Usefulness of the LDL-C/apoB ratio in the overall evaluation of atherogenicity of lipid profile

CONTEXT

The ratio of low-density lipoprotein cholesterol to apolipoprotein-B (LDL-C/apoB) conventionally represents an alternative index of LDL particle size.

OBJECTIVE

This study was undertaken to determine the importance of LDL-C/apoB ratio in the overall evaluation of atherogenicity of lipid profile.

METHODS

The plasma levels of total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), apolipoprotein (apo) A-I, apoB and apoE were measured in 186 apparently healthy men using enzymatic and immunoturbidimetric methods.

RESULTS

The subjects with low values of the LDL-C/apoB ratio, indicating a predominance of small dense LDL (sd-LDL) particles in plasma, were characterized by higher TG levels and lower apoE levels.

CONCLUSION

Low levels of apoE are most likely a cause of reduced clearance of TG-rich lipoproteins, which promotes the formation of sd-LDL. Determination of the LDL-C/apoB ratio can be used for monitoring qualitative changes in lipid profile, in addition to traditional lipid variables indicating quantitative changes.

Saturated Fat Consumption and Risk of Coronary Heart Disease and Ischemic Stroke: A Science Update

At a workshop to update the science linking saturated fatty acid (SAFA) consumption with the risk of coronary heart disease (CHD) and ischemic stroke, invited participants presented data on the consumption and bioavailability of SAFA and their functions in the body and food technology. Epidemiological methods and outcomes were related to the association between SAFA consumption and disease events and mortality. Participants reviewed the effects of SAFA on CHD, causal risk factors, and surrogate risk markers. Higher intakes of SAFA were not associated with higher risks of CHD or stroke apparently, but studies did not take macronutrient replacement into account. Replacing SAFA by cis-polyunsaturated fatty acids was associated with significant CHD risk reduction, which was confirmed by randomized controlled trials. SAFA reduction had little direct effect on stroke risk. Cohort studies suggest that the food matrix and source of SAFA have important health effects.

Method for estimating high sdLDL-C by measuring triglyceride and apolipoprotein B levels

Background

We previously developed an assay to directly measure small dense (sd) low-density lipoprotein cholesterol (LDL-C) levels, which is not widely used in general clinical practice. Therefore, we propose a simpler method, “LDL window,” that uses conventional methods for estimating high sdLDL-C levels.

Methods

We analyzed our previous studies (2006–2008) on healthy subjects and patients with type 2 diabetes and coronary artery disease (CAD). The sdLDL-C level was measured using the precipitation method, and LDL size was determined using gradient gel electrophoresis. The “LDL window” comprises the estimation of LDL particle number and size. We adopted apolipoprotein B (apoB) for the estimation of the LDL particle number and used 110 mg/dL as the cutoff value for hyper-apoB. Triglycerides (TGs) are a powerful inverse determinant of LDL particle size. Therefore, we adopted TG for the estimation of the LDL particle size and used 150 mg/dL as the cutoff value for hyper-TG. Subjects were stratified into the following four subgroups: normal, hyper-TG, hyper-apoB, and hyper-TG/-apoB. Non-high-density lipoprotein cholesterol (non-HDL-C) is a surrogate marker for apoB; therefore, the “alternative LDL window” comprised non-HDL-C (cutoff, 170 mg/dL) and TG.

Results

The top quartile (Q4) of sdLDL-C (>31 mg/dL) doubled in patients with diabetes and CAD. The hyper-TG/-apoB group in the “LDL window” represented >90% Q4 and <4% Q1 and Q2, irrespective of the subjects. The sdLDL-C levels in the hyper-TG/-apoB group were 50% higher in patients with diabetes and CAD than those in controls. Similar results were obtained using the “alternative LDL window.”

Conclusions

Our proposed “LDL window” may help identify patients at high risk of CAD independent of LDL-C.

Electronic supplementary material

The online version of this article (doi:10.1186/s12944-017-0417-6) contains supplementary material, which is available to authorized users.

Dapagliflozin decreases small dense low-density lipoprotein-cholesterol and increases high-density lipoprotein 2-cholesterol in patients with type 2 diabetes: comparison with sitagliptin

Background

The sodium-glucose co-transporter-2 (SGLT-2) inhibitors have been reported to increase both low-density lipoprotein (LDL) and high-density lipoprotein (HDL)-cholesterol (C). This study aimed to determine how SGLT-2 inhibitors affect LDL and HDL-C subspecies.

Methods

This single center, open-label, randomized, prospective study included 80 patients with type 2 diabetes taking prescribed oral hypoglycemic agents. Patients were allocated to receive dapagliflozin (n = 40) or sitagliptin (n = 40) as add-on treatment. Fasting blood samples were collected before and 12 weeks after this intervention. Small dense (sd) LDL-C, large buoyant (lb) LDL-C, HDL2-C, and HDL3-C levels were determined using our established homogeneous assays. Statistical comparison of blood parameters before and after treatment was performed using the paired t test.

Results

Dapagliflozin and sitagliptin comparably decreased HbA1c (0.75 and 0.63%, respectively). Dapagliflozin significantly decreased body weight, systolic blood pressure, plasma triglycerides and liver transaminases, and increased adiponectin; sitagliptin did not alter these measurements. LDL-C and apolipoprotein (apo) B were not significantly changed by dapagliflozin, whereas HDL-C and apo AI were increased. Dapagliflozin did not alter concentrations of LDL-C, but sd LDL-C decreased by 20% and lb LDL-C increased by 18%. Marked elevation in lb LDL-C (53%) was observed in individuals (n = 20) whose LDL-C was elevated by dapagliflozin. However, sd LDL-C remained suppressed (20%). Dapagliflozin increased HDL2-C by 18% without affecting HDL3-C. Sitagliptin did not alter plasma lipids or lipoprotein subspecies.

Conclusions

A SGLT-2 inhibitor, dapagliflozin suppresses potent atherogenic sd LDL-C and increased HDL2-C, a favorable cardiometabolic marker. Although LDL-C levels are elevated by treatment with dapagliflozin, this was due to increased concentrations of the less atherogenic lb LDL-C. However, these findings were not observed after treatment with dipeptidyl peptidase-4 inhibitor, sitagliptin.

Trial registration UMIN Clinical Trials Registry (UMIN000020984)

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-016-0491-5) contains supplementary material, which is available to authorized users.

Insulin Resistance Predicts Atherogenic Lipoprotein Profile in Nondiabetic Subjects

BACKGROUND

Atherogenic diabetes is associated with an increased cardiovascular risk and mortality in diabetic individuals; however, the impact of insulin resistance (IR) in lipid metabolism in preclinical stages is generally underreported. For that, we evaluated the capacity of IR to predict an atherogenic lipid subfraction profile.

METHODS

Complete clinical evaluation and biochemical analysis (lipid, glucose profile, LDL, and HDL subfractions and LDL phenotype and size) were performed in 181 patients. The impact of IR as a predictor of atherogenic lipoproteins was tested by logistic regression analysis in raw and adjusted models.

RESULTS

HDL-C and Apo AI were significantly lower in individuals with IR. Individuals with IR had a higher percentage of small HDL particles, lower percentage in the larger ones, and reduced frequency of phenotype A (IR = 62%; non-IR = 83%). IR individuals had reduced probability to have large HDL (OR = 0.213; CI = 0.999-0.457) and had twice more chances to show increased small HDL (OR = 2.486; CI = 1.341-7.051). IR was a significant predictor of small LDL (OR = 3.075; CI = 1.341-7.051) and atherogenic phenotype (OR = 3.176; CI = 1.469-6.867).

CONCLUSION

IR, previously DM2 diagnosis, is a strong predictor of quantitative and qualitative features of lipoproteins directly associated with an increased atherogenic risk.

Effects of liquid oil vs. oleogel co-ingested with a carbohydrate-rich meal on human blood triglycerides, glucose, insulin and appetite

We examine the difference in how coconut oil in a liquid or oleogel form affects blood triglycerides, glucose, insulin, and appetite when co-ingested with a carbohydrate-rich meal.

Treatment of Dyslipidemias to Prevent Cardiovascular Disease in Patients with Type 2 Diabetes

PURPOSE OF REVIEW

Current preventive and treatment guidelines for type 2 diabetes have failed to decrease the incidence of comorbidities, such as dyslipidemia and ultimately heart disease. The goal of this review is to describe the physiological and metabolic lipid alterations that develop in patients with type 2 diabetes mellitus. Questions addressed include the differences in lipid and lipoprotein metabolism that characterize the dyslipidemia of insulin resistance and type 2 diabetes mellitus. We also examine the relevance of the new AHA/ADA treatment guidelines to dyslipidemic individuals.

RECENT FINDINGS

In this review, we provide an update on the pathophysiology of diabetic dyslipidemia, including the role of several apolipoproteins such as apoC-III. We also point to new studies and new agents for the treatment of individuals with type 2 diabetes mellitus who need lipid therapies. Type 2 diabetes mellitus causes cardiovascular disease via several pathways, including dyslipidemia characterized by increased plasma levels of apoB-lipoproteins and triglycerides, and low plasma concentrations of HDL cholesterol. Treatments to normalize the dyslipidemia and reduce the risk for cardiovascular events include the following: lifestyle and medication, particularly statins, and if necessary, ezetimibe, to significantly lower LDL cholesterol. Other treatments, more focused on triglycerides and HDL cholesterol, are less well supported by randomized clinical trials and should be used on an individual basis. Newer agents, particularly the PCSK9 inhibitors, show a great promise for even greater lowering of LDL cholesterol, but we await the results of ongoing clinical trials.

Hypertriglyceridemia is a major factor associated with elevated levels of small dense LDL cholesterol in patients with metabolic syndrome

BACKGROUND

We aimed to determine the major contributing component of metabolic syndrome (MetS) that results in an elevated small dense LDL cholesterol (sdLDL-C) concentration and sdLDL-C/LDL-C ratio.

METHODS

Four hundred and forty-seven subjects (225 men; 222 women) with MetS were randomly selected from the Korean Metabolic Syndrome Research Initiatives-Seoul cohort study. Age- and sex-matched healthy controls (181 men; 179 women) were also randomly selected from the same cohort.

RESULTS

A comparison of the median values of the sdLDL-C concentration between subgroups, divided according to whether subjects met or did not meet the criteria for each MetS component in patients with MetS, revealed a significant difference in the sdLDL-C concentration only between subgroups divided according to whether subjects met or did not meet the triglyceride (TG) criteria (P<0.05 for each gender). The TG level showed a good correlation with sdLDL-C concentration (correlation coefficients [r]=0.543 for men; 0.653 for women) and the sdLDL-C/LDL-C ratio (r=0.789 for men; 0.745 for women). Multiple linear regression analyses conducted for the MetS group concordantly identified TG as one of the most significant contributors to sdLDL-C concentration (β=0.1747±0.0105, P<0.0001) and the sdLDL-C/LDL-C ratio (β=6.9518±0.3011, P<0.0001).

CONCLUSIONS

Among five MetS components, only the abnormal TG level was a differentiating factor for sdLDL-C concentration and sdLDL-C/LDL-C ratio. These results were reproducible in both genders, with or without MetS.

Do HDL and LDL subfractions play a role in atherosclerosis in end-stage renal disease (ESRD) patients?

BACKGROUND

Significantly increased cardiovascular mortality in patients with chronic kidney (CKD) disease cannot be explained by traditional risk factors. Recent studies revealed that the quality of HDL and LDL cholesterol may be more important than their serum levels. The aim of this study was to assess which LDL and HDL subfractions were more abundant in end-stage renal disease (ESRD) patients and to analyse whether subfraction distribution could be associated with accelerated atherosclerotic processes.

METHODS

This study included 50 ESRD patients undergoing dialysis and 20 healthy volunteers. LDL and HDL subfractions were analysed in serum with the use of Lipoprint system. All patients had intima-media thickness (IMT) measured.

RESULTS

Statistically significant differences in subfractions between control and study group were observed in case of: HDL1 (p < 0.0001), HDL2 (p = 0.009), HDL3 (p < 0.0001), HDL4 (p = 0.003), HDL5 (p = 0.01), HDL7 (p < 0.0001), HDL8 (p < 0.0001), HDL9 (p < 0.0001), HDL10 (p < 0.0001), large HDL (p < 0.0001), HDL Small (p < 0.0001) as well as IDL-B (p = 0.014), IDLA (p = 0.011), LDL2 (p = 0.007). Significant differences were also observed in HDL and LDL subfraction distribution between haemodialysis patients with normal and increased IMT: HDL6 (p = 0.020), HDL Large (HDL1-3) (p = 0.017), HDL Intermediate (HDL4-7) (p = 0.017).

CONCLUSIONS

This study revealed that ESRD influenced HDL subfractions. In HD patients, large HDL subfractions are more abundant while small HDL fraction is more frequent in healthy persons. It failed to show the influence of end-stage disease on LDL subfraction levels. Shift in HDL subfractions might be responsible for the increased risk of atherosclerosis in CKD patients.

Association of dietary intakes of total and subtypes of fat substituted for carbohydrate with metabolic syndrome in Koreans

Amount of fat consumption has gradually increased among Koreans, which is relatively lower than western countries. In the current study, we examined the association between dietary fat and metabolic syndrome (MetS) prevalence among Korean adults. 3,212 participants who are aged 30-74 years from the Korea National Health and Nutritional Examination Survey (KNHANES) VI (2013) were included for cross-sectional analyses. Dietary intake data was assessed using 24-hour recall method, and MetS was defined using guideline of the National Cholesterol Education Program Adult Treatment panel III (NCEP-ATP III). Multivariate logistic regression analysis was used to estimate MetS odds ratios, using nutrient density model, according to 5% percent unit of dietary fat intake. The prevalence of MetS was significantly associated with dietary intake of total fat and saturated fatty acid (SFA) after adjustment (odds ratio [OR] 0.984 95% confidence interval [CI] 0.972-0.996; OR 0.946 95% CI 0.915-0.979). When dietary intake of total fat and SFA were substituted for carbohydrate (CHO), ORs for MetS were 0.985 (95% CI 0.972-0.998) and 0.948 (95% CI 0.907-0.990), respectively, after adjusting for potential covariates. In summary, MetS was significantly associated with dietary intakes of total fat and SFA, and when substituting dietary fat for carbohydrate among Koreans.

Milk and dairy products: good or bad for human health? An assessment of the totality of scientific evidence

Background

There is scepticism about health effects of dairy products in the public, which is reflected in an increasing intake of plant-based drinks, for example, from soy, rice, almond, or oat.

Objective

This review aimed to assess the scientific evidence mainly from meta-analyses of observational studies and randomised controlled trials, on dairy intake and risk of obesity, type 2 diabetes, cardiovascular disease, osteoporosis, cancer, and all-cause mortality.

Results

The most recent evidence suggested that intake of milk and dairy products was associated with reduced risk of childhood obesity. In adults, intake of dairy products was shown to improve body composition and facilitate weight loss during energy restriction. In addition, intake of milk and dairy products was associated with a neutral or reduced risk of type 2 diabetes and a reduced risk of cardiovascular disease, particularly stroke. Furthermore, the evidence suggested a beneficial effect of milk and dairy intake on bone mineral density but no association with risk of bone fracture. Among cancers, milk and dairy intake was inversely associated with colorectal cancer, bladder cancer, gastric cancer, and breast cancer, and not associated with risk of pancreatic cancer, ovarian cancer, or lung cancer, while the evidence for prostate cancer risk was inconsistent. Finally, consumption of milk and dairy products was not associated with all-cause mortality. Calcium-fortified plant-based drinks have been included as an alternative to dairy products in the nutrition recommendations in several countries. However, nutritionally, cow's milk and plant-based drinks are completely different foods, and an evidence-based conclusion on the health value of the plant-based drinks requires more studies in humans.

Conclusion

The totality of available scientific evidence supports that intake of milk and dairy products contribute to meet nutrient recommendations, and may protect against the most prevalent chronic diseases, whereas very few adverse effects have been reported.

Association of lipoprotein subfractions with endothelial function and arterial stiffness in acute ischemic stroke

Hypercholesterolemia represents a risk factor for the development of atherosclerosis. Lipoprotein research has recently been focused on the phenomenon of atherogenic and non-atherogenic lipoproteins. The aim of this study was to explore the association of lipoprotein subfractions with a measure for endothelial function (represented by reactive hyperemia index [RHI]) and arterial stiffness (represented by augmentation index [AI]) in patients with acute ischemic stroke. We enrolled 51 patients with acute ischemic stroke. Blood samples were obtained within 24 h after the stroke onset in a fasting condition. Electrophoresis method on polyacrylamide gel was used for the analysis of plasma lipoproteins. RHI and AI was measured by peripheral arterial tonometry (EndoPAT2000 device). We failed to find any significant correlation between RHI and baseline characteristics of the population. Significant correlation was found between AI and age, hypertension, low density lipoprotein cholesterol (LDL) 1, LDL 3-7, score for anti-atherogenic risk and atherogenic profile. Age (beta = .362, p = .006) and LDL1 (beta = -0.283, p = .031) were the only independent variables significantly associated with AI in regression analysis. Significantly higher AI was found in an atherogenic lipoprotein profile compared to a non-atherogenic profile population (median 25% vs. median 11.5%, p = .043). In conclusion, our results suggest significant inverse correlation between levels of LDL 1 subfraction and measures of AI in patients with acute ischemic stroke. Significantly higher values of AI were observed in the population with an atherogenic lipoprotein profile.

Early Transcriptomic Response to LDL and oxLDL in Human Vascular Smooth Muscle Cells

Background

Although nowadays it is well known that the human transcriptome can importantly vary according to external or environmental condition, the reflection of this concept when studying oxidative stress and its direct relationship with gene expression profiling during the process of atherogenesis has not been thoroughly achieved.

Objective

The ability to analyze genome-wide gene expression through transcriptomics has shown that the genome responds dynamically to diverse stimuli. Here, we describe the transcriptome of human vascular smooth muscle cells (hVSMC) stimulated by native and oxidized low-density lipoprotein (nLDL and oxLDL respectively), with the aim of assessing the early molecular changes that induce a response in this cell type resulting in a transcriptomic transformation. This expression has been demonstrated in atherosclerotic plaques in vivo and in vitro, particularly in the light of the oxidative modification hypothesis of atherosclerosis.

Approach and Results

Total RNA was isolated with TRIzol reagent (Life Technologies) and quality estimated using an Agilent 2100 bioanalyzer. The transcriptome of hVSMC under different experimental conditions (1,5 and 24 hours for nLDL and oxLDL) was obtained using the GeneChip Human Gene 1.0 ST (Affymetrix) designed to measure gene expression of 28,869 well-annotated genes. A fixed fold-change cut-off corresponding to ± 2 was used to identify genes exhibiting the most significant variation and statistical significance (P< 0.05), and 8 genes validated by qPCR using Taqman probes.

Conclusions

10 molecular processes were significantly affected in hVSMC: Apoptosis and cell cycle, extracellular matrix remodeling, DNA repair, cholesterol efflux, cGMP biosynthesis, endocytic mechanisms, calcium homeostasis, redox balance, membrane trafficking and finally, the immune response to inflammation. The evidence we present supporting the hypothesis for the involvement of oxidative modification of several processes and metabolic pathways in atherosclerosis is strengthen by the fact that gene expression patterns obtained when hVSMC are incubated for a long period of time in the presence of nLDL, correspond very much the same as when cells are incubated for a short period of time in the presence of chemically modified oxLDL. Our results indicate that under physiological conditions and directly related to specific environmental conditions, LDL particles most probably suffer chemical modifications that initially serve as an alert signal to overcome a harmful stimulus that with time might get transformed to a pathological pattern and therefore consolidate a pathological condition.

Comprehensive assessment of lipoprotein subfraction profiles according to glucose metabolism status, and association with insulin resistance in subjects with early-stage impaired glucose metabolism

BACKGROUND

Early detection of atherogenic dyslipidemia is crucial. We investigated lipoprotein subfraction parameters according to glucose metabolism status.

METHODS

We recruited 1255 lipid-lowering drug-naïve subjects with normal fasting glucose (NFG; n=200, 15.9%), impaired fasting glucose (IFG; n=443, 35.3%), or type 2 diabetes (T2D; n=612, 48.8%). Lipoprotein subfractions (1-7) were determined by polyacrylamide gel electrophoresis, separating low-density lipoprotein (LDL) into large buoyant LDL (lbLDL, LDL1-2) and small dense LDL (sdLDL, LDL3-7). Lipoprotein subfraction parameters including the sdLDL% (LDL3-7/LDL1-7), the sdLDL/lbLDL ratio (LDL3-7/LDL1-2), and weighted LDL subfraction (LDLSF) scores, were compared between groups. Their associations with insulin resistance, estimated using the homeostasis model assessment of insulin resistance, were examined.

RESULTS

The concentrations of sdLDL particles were significantly higher in subjects with T2D and IFG than in those with NFG (15.78±13.47mg/dl and 14.60±14.33mg/dl, respectively, vs. 12.22±12.31mg/dl). Compared with those with NFG, subjects with IFG or T2D had significantly a higher sdLDL% (15.98±15.26% vs. 19.50±16.21% or 21.46±16.81%, respectively), a higher sdLDL/lbLDL ratio (0.24±0.30 vs. 0.31±0.37 or 0.35±0.39), and a higher LDLSF score (2.08±0.91 vs. 2.30±1.14 or 2.36±1.17). These lipoprotein subfraction parameters had stronger associations with insulin resistance compared to conventional lipid profiles in the IFG and T2D groups.

CONCLUSIONS

Atherogenic dyslipidemia is initiated in an early stage of impaired glucose metabolism, when early intervention might be required.

Comparing effects of soybean oil- and palm olein-based mayonnaise consumption on the plasma lipid and lipoprotein profiles in human subjects: a double-blind randomized controlled trial with cross-over design

BACKGROUND

Mayonnaise is used widely in contemporary human diet with widespread use as a salad dressing or spread on breads. Vegetable oils used in its formulation may be a rich source of ω-6 PUFAs and the higher-PUFA content of mayonnaise may be beneficial in mediating a hypocholesterolemic effect. This study, therefore, evaluated the functionality of mayonnaise on cardiometabolic risk within a regular human consumption scenario.

METHODS

Subjects underwent a randomized double-blind crossover trial, consuming diets supplemented with 20 g/day of either soybean oil-based mayonnaise (SB-mayo) or palm olein-based mayonnaise (PO-mayo) for 4 weeks each with a 2-week wash-out period. The magnitude of changes for metabolic outcomes between dietary treatments was compared with PO-mayo serving as the control. The data was analyzed by ANCOVA using the GLM model. Analysis was adjusted for weight changes.

RESULTS

Treatments resulted in significant reductions in TC (diff = -0.25 mmol/L; P = 0.001), LDL-C (diff = -0.17 mmol/L; P = 0.016) and HDL-C (diff = -0.12 mmol/L; P < 0.001) in SB-mayo compared to PO-mayo without affecting LDL-C:HDL-C ratio (P > 0.05). Lipoprotein particle change was significant with large LDL particles increasing after PO-mayo (diff = +63.2 nmol/L; P = 0.007) compared to SB-mayo but small LDL particles remained unaffected. Plasma glucose, apolipoproteins and oxidative stress markers remained unchanged.

CONCLUSIONS

Daily use with 20 g of linoleic acid-rich SB-mayo elicited reductions in TC and LDL-C concentrations without significantly changing LDL-C:HDL-C ratio or small LDL particle distributions compared to the PO-mayo diet.

TRIAL REGISTRATION

This clinical trial was retrospectively registered with the National Medical Research Register, National Institute of Health, Ministry of Health Malaysia, (NMRR-15-40-24035; registered on 29/01/2015; https://www.nmrr.gov.my/fwbPage.jsp?fwbPageId=ResearchISRForm&fwbAction=Update&fwbStep=10&pk.researchID=24035&fwbVMenu=3&fwbResearchAction=Update ). Ethical approval was obtained from the National University of Malaysia's Medical Ethics Committee (UKM 1.5.3.5/244/SPP/NN-054-2011, approved on 25/05/2011).

Hepatitis C virus G1b infection decreases the number of small low-density lipoprotein particles

AIM: To investigate how hepatitis C virus (HCV) G1b infection influences the particle number of lipoproteins.

METHODS: The numbers of lipoprotein particles in fasting sera from 173 Japanese subjects, 82 with active HCV G1b infection (active HCV group) and 91 with cleared HCV infection (SVR group), were examined. Serum lipoprotein was fractionated by high-performance liquid chromatography into twenty fractions. The cholesterol and triglyceride concentrations in each fraction were measured using LipoSEARCH. The number of lipoprotein particles in each fraction was calculated using a newly developed algorithm, and the relationship between chronic HCV G1b infection and the lipoprotein particle number was determined by multiple linear regression analysis.

RESULTS: The median number of low-density lipoprotein (LDL) particles was significantly lower in the active HCV group [1182 nmol/L, interquartile range (IQR): 444 nmol/L] than in the SVR group (1363 nmol/L, IQR: 472 nmol/L, P < 0.001), as was that of high-density lipoprotein (HDL) particles (14168 nmol/L vs 15054 nmol/L, IQR: 4114 nmol/L vs 3385 nmol/L, P = 0.042). The number of very low-density lipoprotein (VLDL) particles was similar between the two groups. Among the four LDL sub-fractions, the number of large LDL particles was similar between the two groups. However, the numbers of medium (median: 533.0 nmol/L, IQR: 214.7 nmol/L vs median: 633.5 nmol/L, IQR: 229.6 nmol/L, P < 0.001), small (median: 190.9 nmol/L, IQR: 152.4 nmol/L vs median: 263.2 nmol/L, IQR: 159.9 nmol/L; P < 0.001), and very small LDL particles (median: 103.5 nmol/L, IQR: 66.8 nmol/L vs median: 139.3 nmol/L, IQR: 67.3 nmol/L, P < 0.001) were significantly lower in the active HCV group than in the SVR group, respectively. Multiple linear regression analysis indicated an association between HCV G1b infection and the decreased numbers of medium, small, and very small LDL particles. However, active HCV infection did not affect the number of large LDL particles or any sub-fractions of VLDL and HDL particles.

CONCLUSION: HCV G1b infection decreases the numbers of medium, small, and very small LDL particles.

HDL subfractions and very early CAD: novel findings from untreated patients in a Chinese cohort

Coronary artery disease (CAD) in very young individuals is a rare disease associated with poor prognosis. However, the role of specific lipoprotein subfractions in very young CAD patients (≤45 years) is not established yet. A total of 734 consecutive CAD subjects were enrolled and were classified as very early (n = 81, ≤45), early (n = 304, male: 45–55; female: 45–65), and late (n = 349, male: >55; female: >65) groups. Meanwhile, a group of non-CAD subjects were also enrolled as controls (n = 56, ≤45). The lipoprotein separation was performed using Lipoprint System. As a result, the very early CAD patients have lower large high-density lipoprotein (HDL) subfraction and higher small low-density lipoprotein (LDL) subfraction (p < 0.05). Although body mass index was inversely related to large HDL subfraction, overweight did not influence its association with very early CAD. In the logistic regression analysis, large HDL was inversely [OR 95% CI: 0.872 (0.825–0.922)] while small LDL was positively [1.038 (1.008–1.069)] related to very early CAD. However, after adjusting potential confounders, the association was only significant for large HDL [0.899 (0.848–0.954)]. This study firstly demonstrated that large HDL subfraction was negatively related to very early CAD suggestive of its important role in very early CAD incidence.

Diet, lipids, and cardiovascular disease

PURPOSE OF REVIEW

Modulation of diet is the primary lifestyle approach for reducing cardiovascular disease (CVD) risk, with a major focus of current guidelines being to lower LDL cholesterol by reducing intake of saturated fatty acids. However, dietary effects on lipid-related CVD risk factors extend beyond LDL cholesterol, with growing emphasis on the prevention and management of atherogenic dyslipidemia, which includes elevated triglyceride, small dense LDL, and reduced HDL cholesterol, and which is associated with excess adiposity and insulin resistance. We here review recent studies of dietary macronutrient effects on CVD risk that may act through effects on plasma lipid and lipoprotein metabolism.

RECENT FINDINGS

Effects of reducing saturated fatty acids on CVD risk have been evaluated both in terms of the replacement macronutrient(s) and the food and dietary context in which the macronutrients are consumed. Although weight loss remains the most important goal for reducing cardiometabolic risk among overweight and obese individuals, a variety of lines of evidence support limitation of added sugars and processed starches for improving features of atherogenic dyslipidemia.

SUMMARY

Increasing understanding of the complexity of nutrient-disease relationships has shifted the framework for CVD prevention from a focus on macronutrient content of diets to foods and dietary patterns.

Regular-Fat Dairy and Human Health: A Synopsis of Symposia Presented in Europe and North America (2014-2015)

In recent history, some dietary recommendations have treated dairy fat as an unnecessary source of calories and saturated fat in the human diet. These assumptions, however, have recently been brought into question by current research on regular fat dairy products and human health. In an effort to disseminate, explore and discuss the state of the science on the relationship between regular fat dairy products and health, symposia were programmed by dairy industry organizations in Europe and North America at The Eurofed Lipids Congress (2014) in France, The Dairy Nutrition Annual Symposium (2014) in Canada, The American Society for Nutrition Annual Meeting held in conjunction with Experimental Biology (2015) in the United States, and The Federation of European Nutrition Societies (2015) in Germany. This synopsis of these symposia describes the complexity of dairy fat and the effects regular-fat dairy foods have on human health. The emerging scientific evidence indicates that the consumption of regular fat dairy foods is not associated with an increased risk of cardiovascular disease and inversely associated with weight gain and the risk of obesity. Dairy foods, including regular-fat milk, cheese and yogurt, can be important components of an overall healthy dietary pattern. Systematic examination of the effects of dietary patterns that include regular-fat milk, cheese and yogurt on human health is warranted.

Prepregnancy Adverse Lipid Profile and Subsequent Risk of Gestational Diabetes

CONTEXT

Lower low-density lipoprotein (LDL) peak diameter and a predominance of small, dense LDL are associated with type 2 diabetes, but it is unclear whether they are a risk factor for gestational diabetes mellitus (GDM).

OBJECTIVE

To evaluate whether prepregnancy lipid profile predicts the development of GDM during pregnancy.

DESIGN

A nested case-control study among women who participated in a multiphasic health exam, where blood was collected and stored between 1984 and 1996, and who then had a subsequent pregnancy between 1984 and 2009.

SETTING

Kaiser Permanente Northern California.

PARTICIPANTS

Cases were 254 women who developed GDM. Two controls were selected for each case and matched for year of blood draw, age at baseline, age at pregnancy, and number of intervening pregnancies.

MAIN OUTCOME MEASURES

Prepregnancy LDL peak diameter and prepregnancy lipid subfraction concentrations grouped according to size, and the odds of developing GDM.

RESULTS

Women in the lowest quartiles of LDL peak diameter and high-density lipoprotein had increased odds of GDM compared with women in the highest quartiles (odds ratio [95% CI], 2.60 [1.37-4.94] and 1.98 [1.01-3.86], respectively), in multivariable adjusted models. Being in the highest quartile of small and very small LDL subfractions also increased the odds of GDM (2.61 [1.35-5.03] and 2.44 [1.22-4.85], respectively).

CONCLUSIONS

Lower LDL peak diameter size and high-density lipoprotein levels and higher levels of small and very small LDL subfraction groups were present years before pregnancy in women who developed GDM. A prepregnancy atherogenic lipid profile may help identify women at risk of GDM to target for prevention.

Evidence-based assessment of lipoprotein(a) as a risk biomarker for cardiovascular diseases - Some answers and still many questions

The present article is aimed at outlining the current state of knowledge regarding the clinical value of lipoprotein(a) (Lp(a)) as a marker of cardiovascular disease (CVD) risk by summarizing the results of recent clinical studies, meta-analyses and systematic reviews. The literature supports the predictive value of Lp(a) on CVD outcomes, although the effect size is modest. Lp(a) would also appear to have an effect on cerebrovascular outcomes, however the effect appears even smaller than that for CVD outcomes. Consideration of apolipoprotein(a) (apo(a)) isoforms and LPA genetics in relation to the simple assessment of Lp(a) concentration may enhance clinical practice in vascular medicine. We also describe recent advances in Lp(a) research (including therapies) and highlight areas where further research is needed such as the measurement of Lp(a) and its involvement in additional pathophysiological processes.

Cryptolepine, an indoloquinoline alkaloid, in the management of diabetes mellitus and its associated complications

Background:

Effective long-term management is the key to treatment of diabetes mellitus (DM) and its complications.

Aim:

To ascertain the ability of cryptolepine (CRP) in managing DM and some associated complications.

Materials and Methods:

Changes in fasting blood sugar (FBS), body weight, response to thermally-induced pain, and semen quality were assessed in normal and alloxan-induced diabetic rats treated with CRP (10, 30, or 100 mg/kg), glibenclamide (10 mg/kg), or normal saline (2 ml/kg) per os. Hematological profile, liver and kidney function tests, lipid profile, as well as liver, kidney, and pancreas histopathological examinations were also conducted to establish possible effects of CRP treatment.

Results:

CRP treatment reduced (P ≤ 0.001) FBS and body weight, inhibited (P ≤ 0.05 - 0.001) the latency to tail flick or withdrawal from pain stimulus. It did not alter (P > 0.05): Hematological parameters, elevated (P ≤ 0.05 - 0.001) plasma aspartate transaminase, alanine transaminase, and gamma-glutamyl transferase, reduced (P ≤ 0.01) plasma urea, and elevated (P ≤ 0.001) plasma creatinine associated with DM. CRP, however, reversed (P ≤ 0.05 - 0.001) DM-associated elevation (P ≤ 0.05 - 0.001) of plasma cholesterol, triglycerides, and low-density lipoproteins, and the reduction in high-density lipoproteins. CRP (10-30 mg/kg) showed dose-dependent regeneration of β-islet cells but could not repair degenerated liver and kidney tissue. CRP worsens dose-dependently (P ≤ 0.001) reduced sperm quality associated with DM.

Conclusion:

CRP abolishes hyperglycemia, weight loss, cold allodynia, neuropathic pain, and hyperlipidemia as well as pancreatic β-islet cell damage associated with DM. It, however, does not improve liver and kidney damage and lowered semen quality.

Effects of low-carbohydrate diets v. low-fat diets on body weight and cardiovascular risk factors: a meta-analysis of randomised controlled trials

The effects of low-carbohydrate (LC) diets on body weight and cardiovascular risk are unclear, and previous studies have found varying results. Our aim was to conduct a meta-analysis of randomised controlled trials (RCT), assessing the effects of LC diets v. low-fat (LF) diets on weight loss and risk factors of CVD. Studies were identified by searching MEDLINE, Embase and Cochrane Trials. Studies had to fulfil the following criteria: a RCT; the LC diet was defined in accordance with the Atkins diet, or carbohydrate intake of <20% of total energy intake; twenty subjects or more per group; the subjects were previously healthy; and the dietary intervention had a duration of 6 months or longer. Results from individual studies were pooled as weighted mean difference (WMD) using a random effect model. In all, eleven RCT with 1369 participants met all the set eligibility criteria. Compared with participants on LF diets, participants on LC diets experienced a greater reduction in body weight (WMD -2·17 kg; 95% CI -3·36, -0·99) and TAG (WMD -0·26 mmol/l; 95% CI -0·37, -0·15), but a greater increase in HDL-cholesterol (WMD 0·14 mmol/l; 95% CI 0·09, 0·19) and LDL-cholesterol (WMD 0·16 mmol/l; 95% CI 0·003, 0·33). This meta-analysis demonstrates opposite change in two important cardiovascular risk factors on LC diets--greater weight loss and increased LDL-cholesterol. Our findings suggest that the beneficial changes of LC diets must be weighed against the possible detrimental effects of increased LDL-cholesterol.

Non-HDL Cholesterol is a More Superior Predictor of Small-Dense LDL Cholesterol than LDL Cholesterol in Japanese Subjects with TG Levels ＜400 mg/dL

Aim: The Japan Atherosclerosis Society (JAS) guidelines for the diagnosis and treatment of hyperlipidemia in Japanese adults recommend using low-density lipoprotein cholesterol (LDL-C) calculated by Friedewald formula (F_LDL-C) for subjects with triglyceride (TG) levels <400 mg/dL and non-high-density lipoprotein cholesterol (non-HDL-C) levels for subjects with TG levels ≥400 mg/dL. Because small-dense LDL particles are more atherogenic than large LDL particles, we sought the better lipid parameter which was more reflective of the high small-dense LDL-C (sdLDL-C) levels in subjects with TG levels <400 mg/dL.

Methods: This study included 769 Japanese subjects who met our inclusion criteria and underwent an annual health examination, including sdLDL-C analyses.

Results: The correlation coefficient of non-HDL-C for sdLDL-C (r = 0.760) was significantly higher than that of F_LDL-C (r = 0.601). The area under the curve (95% confidence interval) was 0.771 (0.731, 0.811) for F_LDL-C and 0.871 (0.842, 0.901) for non HDL-C, which showed significantly higher predictive value for more than fourth quartile value of sdLDL-C (46 mg/dL). The optimal cut-off point of non-HDL-C was 158 mg/dL. Even in subjects stratified by waist circumstance, homeostasis model assessment of insulin resistance, TG, and F_LDL-C levels and non-HDL-C showed stronger relationships with sdLDL-C than F_LDL-C. Moreover, non-HDL-C showed a better relationship with sdLDL-C than total cholesterol (TC), TC/HDL-C, and non-HDL-C/HDL-C.

Conclusion: Our data suggested that non-HDL-C is superior to F_LDL-C and one of the reliable surrogate lipid markers of sdLDL-C in Japanese subjects with TG levels <400 mg/dL.

Atherosclerosis--do we know enough already to prevent it?

In this review, we have briefly summarized the characteristics of lipids and lipoproteins and the atherosclerotic process. The development of atherosclerosis is a continuous process that involves numerous cellular and acellular processes that influence the behavior of each other. These include oxidative stress, lipoprotein modifications, macrophage polarization, macrophage lipid accumulation, generation of pro- and anti-inflammatory components, calcification, cellular growth and proliferation, and plaque rupture. The precise role(s) of many of these are unknown. Understanding the events at each particular stage might shed more light onto the process as a whole and could potentially reveal targets for intervention. Therapeutic modalities that work at one stage may have little to no influence on other stages of the disease.

Management of Hypertriglyceridemia for Prevention of Atherosclerotic Cardiovascular Disease

Mendelian randomization data strongly suggest that hypertriglyceridemia (HTG) causes atherosclerotic cardiovascular disease (ASCVD), and so triglyceride (TG) level-lowering treatment in HTG is now more strongly recommended to address the residual ASCVD risk than has been the case in (generally earlier) published guidelines. Fibrates are the best-established agents for TG level lowering and are generally used as first-line treatment of TG levels greater than 500 mg/dL. Statins are the best-established agents for ASCVD prevention, and so are usually used as first-line treatment of TG levels less than 500 mg/dL.

Hepatic Effects of Estrogen on Plasma Distribution of Small Dense Low-Density Lipoprotein and Free Radical Production in Postmenopausal Women

AIM

Hepatic effects of estrogen therapy on low-density lipoprotein (LDL) subfraction or oxidative stress have not been previously evaluated. The purpose of the present study was to investigate whether the differential hepatic effects of estrogen affect plasma distribution of small dense LDL and free radical production in postmenopausal women.

METHODS

In all, 45 postmenopausal women were given 0.625 mg/day of oral conjugated equine estrogen (CEE) (n=15), 1.0 mg/day of oral 17β estradiol (E2) (n=15), or 50 μg/day of transdermal 17βE2 (n=15) for 3 months. Subjects received either estrogen alone or with dydrogesterone at 5 mg/day. Plasma concentrations of sex hormone-binding globulin (SHBG), lipids, metallic ions, and derivatives of reactive oxygen metabolites (d-ROMs) were measured.

RESULTS

CEE, but not oral 17βE2, increased the plasma concentrations of triglyceride, copper (Cu), and d-ROMs and the ratio of small dense LDL/total LDL cholesterol, a marker for plasma distribution of small dense LDL. Transdermal 17βE2 decreased d-ROMs concentrations but did not significantly change other parameters. Plasma concentrations of SHBG increased in the 3 groups. Estrogen-induced changes in triglyceride correlated positively either with changes in SHBG (R=0.52, P=0.0002) or the ratio of small dense LDL/total LDL cholesterol (R=0.65, P＜0.0001). Changes in Cu also correlated positively either with changes in SHBG (R=0.85, P＜0.0001) or d-ROMs (R=0.86, P＜0.0001).

CONCLUSION

The hepatic effects of different routes or types of estrogen therapy may be associated with plasma distribution of small dense LDL and free radical production in postmenopausal women.

The relation of saturated fatty acids with low-grade inflammation and cardiovascular disease

The mantra that dietary (saturated) fat must be minimized to reduce cardiovascular disease (CVD) risk has dominated nutritional guidelines for decades. Parallel to decreasing intakes of fat and saturated fatty acids (SFA), there have been increases in carbohydrate and sugar intakes, overweight, obesity and type 2 diabetes mellitus. The "lipid hypothesis" coined the concept that fat, especially SFA, raises blood low-density lipoprotein-cholesterol and thereby CVD risk. In view of current controversies regarding their adequate intakes and effects, this review aims to summarize research regarding this heterogenic group of fatty acids and the mechanisms relating them to (chronic) systemic low-grade inflammation, insulin resistance, metabolic syndrome and notably CVD. The intimate relationship between inflammation and metabolism, including glucose, fat and cholesterol metabolism, revealed that the dyslipidemia in Western societies, notably increased triglycerides, "small dense" low-density lipoprotein and "dysfunctional" high-density lipoprotein, is influenced by many unfavorable lifestyle factors. Dietary SFA is only one of these, not necessarily the most important, in healthy, insulin-sensitive people. The environment provides us not only with many other proinflammatory stimuli than SFA but also with many antiinflammatory counterparts. Resolution of the conflict between our self-designed environment and ancient genome may rather rely on returning to the proinflammatory/antiinflammatory balance of the Paleolithic era in consonance with the 21st century culture. Accordingly, dietary guidelines might reconsider recommendations for SFA replacement and investigate diet in a broader context, together with nondietary lifestyle factors. This should be a clear priority, opposed to the reductionist approach of studying the effects of single nutrients, such as SFA.

Genetics of non-conventional lipoprotein fractions

Lipoprotein subclass measures associate with cardiometabolic disease risk. Currently the information that lipoproteins convey on disease risk over that of traditional demographic and lipid measures is minimal, and so their use is clinics is limited. However, lipoprotein subclass perturbations represent some of the earliest manifestations of metabolic dysfunction, and their etiology is partially distinct from lipids, so information on the genetic etiology of lipoproteins offers promise for improved risk prediction, and unique mechanistic insights into IR and atherosclerosis. Here, I review the genetic variants validated as associating with lipoprotein measures to date, and show that the majority of identified variants have functionality that is best understood as related to lipid measures. Until we focus on the genes as they relate to lipoprotein subclass production, we are limiting our understanding of biological mechanisms underlying cardiometabolic disease.

A review of low-density lipoprotein cholesterol, treatment strategies, and its impact on cardiovascular disease morbidity and mortality

Cardiovascular (CV) disease is a leading cause of death worldwide, accounting for approximately 31.4% of deaths globally in 2012. It is estimated that, from 1980 to 2000, reduction in total cholesterol accounted for a 33% decrease in coronary heart disease (CHD) deaths in the United States. In other developed countries, similar decreases in CHD deaths (ranging from 19%-46%) have been attributed to reduction in total cholesterol. Low-density lipoprotein cholesterol (LDL-C) has now largely replaced total cholesterol as a risk marker and the primary treatment target for hyperlipidemia. Reduction in LDL-C levels by statin-based therapies has been demonstrated to result in a reduction in the risk of nonfatal CV events and mortality in a continuous and graded manner over a wide range of baseline risk and LDL-C levels. This article provides a review of (1) the relationship between LDL-C and CV risk from a biologic, epidemiologic, and genetic standpoint; (2) evidence-based strategies for LDL-C lowering; (3) lipid-management guidelines; (4) new strategies to further reduce CV risk through LDL-C lowering; and (5) population-level and health-system initiatives aimed at identifying, treating, and lowering lifetime LDL-C exposure.

Interaction between Glucose and Lipid Metabolism: More than Diabetic Dyslipidemia

Glucose and lipid metabolism are linked to each other in many ways. The most important clinical manifestation of this interaction is diabetic dyslipidemia, characterized by elevated triglycerides, low high density lipoprotein cholesterol (HDL-C), and predominance of small-dense LDL particles. However, in the last decade we have learned that the interaction is much more complex. Hypertriglyceridemia and low HDL-C cannot only be the consequence but also the cause of a disturbed glucose metabolism. Furthermore, it is now well established that statins are associated with a small but significant increase in the risk for new onset diabetes. The underlying mechanisms are not completely understood but modulation of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG CoA)-reductase may play a central role as genetic data indicate that mutations resulting in lower HMG CoA-reductase activity are also associated with obesity, higher glucose concentrations and diabetes. Very interestingly, this statin induced increased risk for new onset type 2 diabetes is not detectable in subjects with familial hypercholesterolemia. Furthermore, patients with familial hypercholesterolemia seem to have a lower risk for type 2 diabetes, a phenomenon which seems to be dose-dependent (the higher the low density lipoprotein cholesterol, the lower the risk). Whether there is also an interaction between lipoprotein(a) and diabetes is still a matter of debate.

Small Dense Low Density Lipoprotein Cholesterol, Paraoxonase 1 and Lipid Profile in Postmenopausal Women: Quality or Quantity?

BACKGROUND AND AIMS

Atherosclerosis, the root cause of cardiovascular disease (CVD), has a number of risk factors-some modifiable and some not. CVD increases in women particularly during the postmenopausal period. Small dense low-density lipoprotein (sdLDL), a subclass of LDL, is an important determinant of atherosclerosis in postmenopausal women. Paraoxonase1 (PON1) is a high-density lipoprotein (HDL)-associated enzyme that prevents oxidative modifications in LDL and HDL. With this background, we studied the sdLDL-C, PON1 and lipid profile in postmenopausal women to compare between quality and quantity of LDL.

METHODS

We studied 80 pre- and postmenopausal women (40/group). The following parameters were studied: lipid profile, sdLDL-C and PON1 levels. With proper statistical tools the correlation between these parameters was studied.

RESULTS

Postmenopausal women, in comparison with premenopausal women, have significantly increased levels of serum triglycerides and sdLDL-C and very-low-density lipoprotein cholesterol (VLDL-C) and significantly decreased levels of HDL-C and PON1. PON1 activity was negatively correlated with age, TC, TG, LDL-C and sdLDL-C (r = -0.574, -0.119, -0.226, -0.473 and -0.455, respectively) and positively correlated with HDL-C (r = 0.368), whereas sdLDL-C was positively correlated with age, TC, TG, LDL-C (r = 0.633, 0.485, 0.561 and 0.705, respectively) and negatively with HDL-C (r = -0.235). Stepwise multiple regression analysis demonstrated HDL-C and menopausal status as the best determinant for PON1 (R(2) = 0.320, p < 0.05) and menopausal status, LDL-C, TG, and TC were the best determinants for sdLDL-C (R(2) = 0.606, p < 0.05).

CONCLUSION

The results of the present study suggest quality, i.e., sdLDL-C, is more important than only LDL-C levels. Similarly, decrease in PON1 and increase in sdLDL-C go hand in hand. This shows that antioxidant capacity is compromised with a qualitative downfall in lipoproteins in postmenopausal women.

Circulating non-HDL-C levels were more relevant to atherogenic lipoprotein subfractions compared with LDL-C in patients with stable coronary artery disease

BACKGROUND

Conflicting results have been yielded as to whether low-density lipoprotein (LDL) cholesterol (LDL-C) or non-high-density lipoprotein (HDL) cholesterol (non-HDL-C) is a better marker of coronary artery disease (CAD) risk. Recently, plasma LDL and HDL subfractions have been suggested to be more accurately reflecting the lipoproteins' atherogenicity.

OBJECTIVE

We sought to compare the relationship between LDL-C or non-HDL-C and lipoprotein subfractions.

METHODS

We conducted a cross-sectional study in 351 consecutive stable CAD patients without lipid-lowering therapy. The LDL and HDL separations were performed using the Lipoprint System. The LDL-C levels were measured directly, and the non-HDL-C levels were calculated.

RESULTS

The cholesterol concentrations of LDL (large, medium, and small) and HDL (small) particles were increased (all P < .001) by non-HDL-C or LDL-C quartiles, whereas the mean LDL particle size and cholesterol concentrations of HDL (large) were decreased (both P < .001) by non-HDL-C quartiles. In age- and gender-adjusted analysis, the cholesterol in small LDL was much strongly related to non-HDL-C than to LDL-C (r = 0.539 vs 0.397, both P < .001). Meanwhile, the mean LDL particle size was more closely associated with non-HDL-C than LDL-C (r = -0.336 vs r = -0.136, both P < .05). Significantly, the cholesterol in large HDL was negatively correlated with non-HDL-C (r = -0223, P < .001) but not with LDL-C. These correlations were further confirmed by the fully adjusted multivariable linear regression analysis.

CONCLUSIONS

Non-HDL-C, in comparison to LDL-C, was more relevant to atherogenic lipoprotein subfractions in patients with stable CAD, supporting that it may be better in assessing cardiovascular risk.

A comparative study of four independent methods to measure LDL particle concentration

BACKGROUND

Low-density lipoprotein particle concentration (LDL-P) is generally more predictive of clinical cardiovascular endpoints than LDL cholesterol (LDL-C). Few studies have directly compared multiple LDL-P methods, particularly with ultracentrifugation.

OBJECTIVE

Examine comparability and precision of 4 LDL-P methods.

METHODS

We divided serum from 48 subjects into blinded triplicates and measured LDL-P in 3 separate laboratories by 4 methods: ultracentrifugation (reference method), a novel electrophoretic method, and nuclear magnetic resonance spectroscopy (NMR) by 2 independent methods: a 400 MHz Vantera(®) instrument supplied by Liposcience (LS-NMR) and operated at ARUP Laboratories, and a 600 MHz Bruker instrument (ASCEND 600) operated at Health Diagnostic Laboratory (HD-NMR).

RESULTS

Of the 4 methods, ultracentrifugation was the most precise and LS-NMR the least; the latter had a significantly greater CV (p < 0.0001) as compared with all 3 of the other methods, although all CVs were clinically acceptable. The electrophoretic method showed similar precision to ultracentrifugation, while HD-NMR was intermediate. The HD-NMR had the slope closest to 1 (0.90, 95% CI 0.71 to 1.09) and the intercept closest to 0 (-48, -353 to 256) compared to the ultracentrifugation method in Deming regression models. While the two NMR methods correlated well (r = 0.95) with each other and had a slope equivalent to 1 (1.08, 0.98 to 1.19), their intercept in Deming regression excluded 0 (194, 53 to 335) indicating a vertical shift between the two methods.

CONCLUSIONS

This LDL-P method comparison may prove useful for future research and clinical applications.

LDL electronegativity index: a potential novel index for predicting cardiovascular disease

High cardiovascular risk conditions are frequently associated with altered plasma lipoprotein profile, such as elevated low-density lipoprotein (LDL) and LDL cholesterol and decreased high-density lipoprotein. There is, however, accumulating evidence that specific subclasses of LDL may play an important role in cardiovascular disease development, and their relative concentration can be regarded as a more relevant risk factor. LDL particles undergo multiple modifications in plasma that can lead to the increase of their negative charge. The resulting electronegative LDL [LDL(–)] subfraction has been demonstrated to be especially atherogenic, and became a subject of numerous recent studies. In this review, we discuss the physicochemical properties of LDL(–), methods of its detection, atherogenic activity, and relevance of the LDL electronegativity index as a potential independent predictor of cardiovascular risk.

Cardiovascular protection by ezetimibe and influence on oxidative stress in mice exposed to intermittent hypoxia

Ezetimibe is as an inhibitor of NPC1L1 protein, which has a key role in cholesterol absorption. The aim of this study was to evaluate the influence of ezetimibe on the plasma lipid profile, atherosclerotic lesions, and cardiomyocyte ultrastructure in an animal model of atherosclerosis with intermittent hypoxia. Apolipoprotein E-knockout mice received a high-fat diet for 30 days. Then animals were exposed to intermittent hypoxia for 10 days or were maintained under normoxic conditions. In the ezetimibe group, ezetimibe (5 mg/kg/day) was added to the diet. Under normoxic conditions, the total cholesterol level was significantly lower in the ezetimibe group (63.6±6.6 mg/dl) than in the control group (116.3±16.9 mg/dl, P<0.001). Intermittent hypoxia accelerated atherosclerosis associated with increased superoxide production, which also caused degeneration of cardiomyocytes, mitochondrial abnormalities, and interstitial fibrosis. Compared with the control group, the ezetimibe group showed significantly less advanced atherosclerotic lesions and lower superoxide production in the thoracic aorta, as well as reduced oxidative stress, preservation of cardiomyocyte ultrastructure, and reduced interstitial fibrosis in the left ventricular myocardium. In conclusion, ezetimibe not only reduces total cholesterol, but also prevents the development of atherosclerosis and cardiovascular events due to intermittent hypoxia at least partly through suppression of oxidative stress.